Thermographic signal analysis of friction stir welded AA 5754 H111 joints

Palumbo, Davide; Finis, Rosa De; Serio, Livia Maria; Galietti, Umberto; Filippis, Luigi Alberto Ciro De

doi:10.1117/12.2304984

Cited by 3 publications

(2 citation statements)

References 15 publications

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“…To assess the location and the time of damage onset, thermographic methods have been used to achieve information about the damage [100][101][102][103][104]. Palumbo et al [105] monitored the AA5754-H111 specimens by infrared detector during experiment and the thermal signal is related to the energy dissipated in the material plastic deformation zones. The fatigue strength was then computed by a graphical study of the location of damaged areas.…”

Section: Experimental Techniquesmentioning

confidence: 99%

Fatigue of Friction Stir Welded Aluminum Alloy Joints: A Review

Gao

2018

Applied Sciences

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The application fields of friction stir welding technology, such as aerospace and transportation, has high safety requirements and fatigue is the dominant failure mode for weldments. It is of great significance to understand the fatigue properties of friction stir welded joints. This paper provides an overview of the fatigue mechanism, influencing factors, crack growth rate, and fatigue life assessment. It is found that the fatigue performance of friction stir welded joints can be affected by welding process parameters, test environment, stress ratio, residual stress, and weld defect. The optimized process parameters can produce high quality weld and increase the weld fatigue life. Laser peening is an effective post weld treatment to decrease fatigue crack growth rate and improve material fatigue life.

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Section: Experimental Techniquesmentioning

confidence: 99%

Fatigue of Friction Stir Welded Aluminum Alloy Joints: A Review

Gao

2018

Applied Sciences

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“…As different fatigue crack initiation sites of heterogeneous structure show disparate fatigue crack propagation paths. Meanwhile, the fatigue crack growth rate and the critical crack propagation size are material-related physical quantities [18,19], which is proved by various fatigue limit assessment techniques [20][21][22][23][24][25][26]. Consequently, changes in the geometric proportions of the constituent materials on the fatigue crack propagation path will directly affect the maximum fatigue bearing capacity of the heterogeneous material.…”

Section: Introductionmentioning

confidence: 99%

Nominal Stress-Based Equal-Fatigue-Bearing-Capacity Design of under-matched HSLA Steel Butt-welded Joints

Wen

Wang

Dong

et al. 2018

Metals

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Under-matched welds could minimize the tendency of cold cracking and reduce the preheating operations when high strength steels are welded. However, its low load-carrying capacity might make the high strength parent metal meaningless. With the aim of improving the fatigue limit of under-matched butt-welded joints, this work establishes a nominal stress based fatigue design method for under-matched butt welds while considering its heterogeneous mechanical features. The fatigue life of the base metal is set to be the design goal for the under-matched butt-welded joints, which has scarce been tried before. An equal-fatigue-bearing capacity (EFBC) design method fit for the under-matched butt-welded joints is thus applied with the aims of equal fatigue limit of base metal. X-shaped butt-welded joint is selected to carry out experimental verification where HSLA steel Q550 as the base metal and ER70S-6 as the under-matched filler metal are used. The results show that the EFBC method proposed here is feasible. Note that the EFBC method is valid only in high cycle fatigue.

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Online monitoring of direct laser metal deposition process by means of infrared thermography

D’Accardi,

Chiappini,

Giannasi

et al. 2023

Prog Addit Manuf

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Direct laser metal deposition (LMD–DED) is an additive manufacturing (AM) process that is used to build up and repair high-quality metal components. It works by overlapping layers of powder material and melting them with a laser. To get a stable process without defects and to reach, at the same time, high mechanical properties, a robust assessment and control of the process parameters, and above all of their combination, is required. The ideal goal is to assure the online control, to stop or correct the process in case of unexpected anomalies. In this work, a robust online monitoring of the laser metal deposition (LMD–DED) process based on the use of infrared thermography was developed and proposed. After choosing the suitable process parameters, a customized design of experiments (DOE) was set, and the statistical analysis of different thermal features was carried out to develop the most robust models that correlate them with the input process parameters (laser power, scanning speed, and powder flow rate). The proposed procedure was based on the extraction of different thermal features from suited regions of interest (ROI), performing statistical analyses by means of analysis of variance (ANOVA) and building regression models to correlate the process parameters with the thermal behavior. The obtained results demonstrated the possibility to control the process by means of the chosen thermal features, independent of the position of the ROI. Moreover, the possibility to use the models to detect typical AM defects, and anomalies, online directly during the process, has been proved and verified by destructive macrographs carried out on the manufactured coupons.

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Thermographic signal analysis of friction stir welded AA 5754 H111 joints

Cited by 3 publications

References 15 publications

Fatigue of Friction Stir Welded Aluminum Alloy Joints: A Review

Fatigue of Friction Stir Welded Aluminum Alloy Joints: A Review

Nominal Stress-Based Equal-Fatigue-Bearing-Capacity Design of under-matched HSLA Steel Butt-welded Joints

Online monitoring of direct laser metal deposition process by means of infrared thermography

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